Include namespace in fragment struct type names

to make sure that if the fragment is used in a query that has a node (and therefore type name) with the same name as the fragment's type name, Swift doesn't get confused about which type is being referred to.

Author: RobinDaugherty

CHANGELOG.md

@@ -11,7 +11,7 @@
 - `apollo-codegen-scala`
   - <First `apollo-codegen-scala` related entry goes here>
 - `apollo-codegen-swift`
-  - <First `apollo-codegen-swift` related entry goes here>
+  - Add namespace when a fragment struct is referenced (Fixes #2396) [PR #2397](https://github.com/apollographql/apollo-tooling/pull/2397)
 - `apollo-codegen-typescript`
   - <First `apollo-codegen-typescript` related entry goes here>
 - `apollo-codegen-core`

packages/apollo-codegen-swift/src/codeGeneration.ts

@@ -339,7 +339,9 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
     outputIndividualFiles: boolean,
     suppressMultilineStringLiterals: boolean
   ) {
-    const structName = this.helpers.structNameForFragmentName(fragmentName);
+    const structName = this.helpers.structDeclarationNameForFragmentName(
+      fragmentName
+    );
 
     this.structDeclarationForSelectionSet(
       {

packages/apollo-codegen-swift/src/helpers.ts

@@ -125,7 +125,22 @@ export class Helpers {
     return pascalCase(Inflector.singularize(propertyName));
   }
 
+  /**
+   * Returns the Swift name for a struct representing a fragment. This must contain
+   * the application namespace in case the fragment name is the same as the name of any
+   * field in the current query, otherwise, Swift will assume the type reference is to
+   * the struct that we're inside the namespace of.
+   */
   structNameForFragmentName(fragmentName: string) {
+    const prefix = this.options?.namespace ? `${this.options.namespace}.` : "";
+    return `${prefix}${pascalCase(fragmentName)}`;
+  }
+
+  /**
+   * Returns the Swift struct name that is being declared. When declaring a struct in Swift,
+   * no namespace can be included in the name.
+   */
+  structDeclarationNameForFragmentName(fragmentName: string) {
     return pascalCase(fragmentName);
   }